Objective  The application of vermicompost in the production of protected vegetables can promote the growth and development of vegetables and improve the yield and quality, but the optimal proportion of vermicompost to replace chemical fertilizer needs to be clarified.

  Method  The 100% chemical fertilizer (100% CF) treatment and no fertilization treatment (CK) were used as control treatments to study the effects of different proportions of vermicompost (VM) combined with chemical fertilizer on K absorption, fruit yield and quality of cucumber in greenhouse.

  Result  The K content, biomass and yield of cucumber plants with 25% reduction in chemical fertilizer application did not decrease significantly compared with the 100% chemical fertilizer treatment. The K uptake, fruit yield and quality of cucumber were significantly improved in the treatment of vermicompost replacing 25% chemical fertilizer. The yield increased by 14.51%, and the plant K uptake increased by 42.27%. The nitrate content of cucumber fruit was significantly reduced when vermicompost replaced 50% chemical fertilizer, but there was no significant difference in K uptake, biomass and yield. The 100% vermicompost treatment resulted in a significant decrease in K uptake, biomass, yield and quality. The yield decreased by 24.25%, and the soluble solid content in the fruit decreased by 15.59%.

  Conclusion  The vermicompost could replace 25% of chemical fertilizer under the condition of equal nutrients, which can promote the K absorption by plants, and improve the yield and quality.